Variable flexibility catheter support frame

ABSTRACT

A guide catheter extension, including a push member having a lumen, a proximal end and a distal end; a tube frame defining a lumen therein, a longitudinal axis, and a proximal segment and a distal segment, wherein the tube frame comprises a plurality of cut patterns therein; and a tongue element extending from the proximal segment of the tube frame, wherein the tongue element is coupled to the push member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/255,141, filed Jan. 23, 2019, which is a continuation-in-part of U.S.patent application Ser. No. 15/726,024, filed Oct. 5, 2017, whichapplication claims priority to U.S. Provisional Application No.62/404,552, filed Oct. 5, 2016, the disclosures of which areincorporated by reference herein in their entirety. This application isalso a continuation-in-part of U.S. patent application Ser. No.15/522,216, filed Apr. 26, 2017, which application claims priority toPCT Application, PCT/US15/58969, filed Nov. 4, 2015, the disclosures ofwhich are incorporated by reference herein in their entirety. Theapplication claims priority to U.S. Patent Application Ser. No.62/729,282 filed Sep. 10, 2018.

BACKGROUND

In coronary artery disease, the coronary arteries may be narrowed oroccluded by atherosclerotic plaques or other lesions. These lesions maytotally obstruct the lumen of the artery or may dramatically narrow thelumen of the artery. In order to diagnose and treat obstructive coronaryartery disease, it is commonly necessary to pass a guidewire or otherinterventional instruments through and beyond the occlusion or stenosisof the coronary artery.

Percutaneous coronary intervention (PCI), also known as coronaryangioplasty, is a therapeutic procedure used to treat the narrowed orstenotic section of the coronary artery of the heart due to coronarylesions or obstructions. A guide catheter may be used in PCI to supporteasier passage for another catheter or interventional device, such as, amicrocatheter, stents or balloons, to access the target site. Forexample, the guide catheter can be inserted through the aorta and intothe ostium of the coronary artery. Once seated in the opening or ostiumof the coronary artery a guidewire or other instrument can be passedthrough the lumen of the guide catheter and then inserted into theartery distal to the occlusion or stenosis. Another example for the useof a guide catheter is found in femoro-popliteal intervention wherefemoral artery intervention can be effectively performed using radial orpedal access with guide catheters. Ruza et al. JAAC 11:1062 (2018).

However, guide catheters may encounter certain difficulties. The anatomyin the area for placement, e.g., the coronary vasculature, may betortuous and the lesions themselves may be comparatively non-compliant.Moreover, when crossing comparatively non-compliant lesions, a backwardforce sufficient to dislodge the guide catheter from the ostium of theartery being treated can be generated. In order to improve backupsupport, U.S. RE 45,830 discloses a coaxial guide catheter which isadapted to be passable within a guide catheter. The distal portion ofthe coaxial guide catheter can be extended distally from the distal endof the guide catheter. The coaxial guide catheter includes a flexibletip portion defining a tubular structure having a lumen through whichinterventional cardiology devices such as stents and balloons can beinserted.

The guide catheter extension devices disclosed or available requireconstruction of different tube portions of different characteristics andjoining these tube portions together. For example, as disclosed in U.S.RE 45,830, the catheter extension includes a catheter tube portion whichmay include a soft tip, an inner liner component, a reinforced portionof the catheter body that is braided or coiled over the inner liner(flat or round wire braid composition or flat or round metal coil) and apolymeric cover section (e.g., Pebax, Nylon or other polymer material)which is melted or recovered over the reinforced catheter section, and asubstantially rigid portion which may be made of stainless steel ornitinol tube. RE 46,116, RE45,760.

Another example of guide catheter design shows a guide catheter having acollar transition is made of a different material from the tubularportion. Here, the tubular portion is formed from multi-filament braidedwire in order to reinforce the polymeric section. See, e.g., U.S. Pat.Nos. 8,048,032, 8,996,095, 9,352,123, 9,687,634, 9,764,118 and9,993,613. However, these multicomponent designs and fabricationrequirements can limit the mechanical properties and make fabricationcomplicated.

Thus, there remains a need for improved design for catheter bodies andcatheter segments such as guide catheter extensions, and more generally,alternative designs for catheter tubes, that allow not only ease offabrication, but also control of various characteristics of the tube,e.g., axial torque transmission, steerability, variable bendingflexibility along the working length, pushability, collapse or kinkresistance, etc., at any point along the tube. Controlling torqueabilityand flexibility at key points along the length of a catheter areimportant in order to enable the physician to negotiate access throughvarious complex and often tortuous, anatomical vasculature which isoften found in the coronary, peripheral or neurovascular systems.

SUMMARY OF THE INVENTION

The present disclosure provides a guide catheter extension, including: apush member having a lumen, a proximal end and a distal end; a tubeframe defining a lumen therein, a longitudinal axis, and a proximalsegment and a distal segment, wherein the tube frame comprises aplurality of cut patterns therein; and a tongue element extending fromthe proximal segment of the tube frame, wherein the tongue element iscoupled to the push member. The push member may include a plurality ofcut patterns therein. The push member may include a plurality ofinterrupted spiral cut patterns.

The cut patterns of the tube frame may include a plurality ofinterrupted spiral-cut patterns. The plurality of interrupted spiral-cutpatterns may extend along a length of the tube frame having an averagestiffness between 0.002-0.004 N/mm. The plurality of interruptedspiral-cut patterns may extend along a length of the tube frame havingan average stiffness of 0.003 N/mm.

The cut patterns of the tube frame may include a continuous spiral-cutpattern. The continuous spiral-cut pattern may extend along a length ofthe tube frame having an average stiffness between 0.001-0.003 N/mm. Thecontinuous spiral-cut pattern may extend along a length of the tubeframe having an average stiffness of 0.002 N/mm.

The cut patterns of the tube frame may include a plurality of ringscoupled together by a plurality of struts, wherein the rings are spacedapart from each other by a cut width, each ring having a width and eachstrut having a width and a length. The plurality of rings may extendalong a length of the tube frame having an average stiffness between0.005-0.016 N/mm N/mm. The rings may be oriented perpendicular to thelongitudinal axis of the tube frame. The rings may be positioned at thedistal segment of the tube frame. The plurality of struts can form atleast one helical pattern in the distal segment of the tube frame. Theplurality of struts may be aligned in at least one line that runssubstantially parallel to the longitudinal axis of the tube frame. Thestruts may be positioned on every other pair of rings. The struts inadjacent rings may be angularly offset from one another at a radialangle ranging from about 5 degrees and about 180 degrees. A hypotheticalplane formed by bisecting the tube frame at the proximal end of the tubeframe may be perpendicular to the longitudinal axis of the tube frame.

The tube frame may include a plurality of protrusions which extend fromthe proximal end of the tube frame. The protrusions may terminate at aplurality of points that lie on a hypothetical plane that isperpendicular to the longitudinal axis of the tube frame. Theprotrusions can be coupled to a flare.

The cut patterns of the tube frame may include at least one zone along aportion of the length of the tube, the zone comprising a plurality ofunits, wherein the units of the zone are distributed circumferentiallyaround the tube in at least one first band, each unit of the zonecomprises at least one cutout segment that is oriented around a centerof symmetry, wherein the center of symmetry of each unit in the band ispositioned equally from the center of symmetry of an adjacent unit inthe same band and the center of symmetry of each unit is positioned atthe same point on the circumference of the tube as the center ofsymmetry of a second unit in a third band which is separated by one bandfrom the first band; a skived collar transition section disposedadjacent the tube, the transition section having a tapered edge, a shortend and a long end; and a push member attached at the long end of thetransition section. The at least one zone can extend along a length ofthe tube frame having an average stiffness between 0.002-0.004 N/mm. Theat least one zone may extend along a length of the tube frame having anaverage stiffness of 0.003 N/mm. Each unit comprises three cutoutsegments extending radially from a center of symmetry of the unit,wherein each cutout segment of the unit is positioned 120° degrees fromthe other cutout segments in the unit in the band.

The guide catheter extension may further include seven zones—a firstzone, a second zone, a third zone, a fourth zone, a fifth zone, a sixthzone and a seventh zone, each zone having is formed from a plurality ofunits, wherein rank order of cutout surface area and cut-patternperimeter length is: unit of the first zone<unit of the second zone<unitof the third zone<unit of the fourth zone<unit of the fifth zone<unit ofthe sixth zone<unit of the seventh zone. The zones may be arranged insequence as first zone, second zone, third zone, fourth zone, fifthzone, sixth zone and seventh zone.

The cut patterns of the tube frame may include a single cut pattern. Thecut patterns of the tube frame may include at least two cut patternsselected from the group consisting of continuous spirals, interruptedspirals, interconnected rings and zones or combinations thereof. Atleast one uncut segment of the tube frame can be disposed between twocut patterns. At least one uncut segment can be disposed along the tubeframe.

At least a portion of the lumen of the tube frame may include a polymerliner bonded to the inner wall of the tube frame by at least one area ofcontact between the polymer liner and the inner wall along the length ofthe tube. The polymer liner can form a tube, and the tube may bepositioned co-axially within the lumen of the tube frame. The polymerliner may include at least two polymer layers, wherein each polymerlayer has a different glass transition temperature. The polymer layeradjacent to the inner wall of the tube frame may have a lower glasstransition temperature (melt temperature) than the polymer layeradjacent to the lumen of the tube frame. The polymer liner can be bondedto the inner wall of the tube at a plurality of areas of contact betweenthe polymer liner and the inner wall along the length of the tube. Thepolymer liner may be bonded continuously to the inner wall of the tubeframe along the length of the tube. The areas of contact may be spacedapart from one another along the longitudinal axis of the tube by adistance ranging from about 1 mm to about 2.5 cm. The polymer liner maybe bonded to the inner wall of the tube frame in a continuous helicalpattern running along at least a portion of the length of tube frame.The polymer liner may be bonded to the inner wall of the tube frame bymelting the polymer to the tube at selected areas of contact. Thepolymer liner may be bonded to the inner wall of the tube frame by anadhesive. The polymer layer adjacent to the inner wall of the tube canbe a polyether block amide, and the polymer layer adjacent to the lumenof the tube frame can be polytetrafluoroethylene (PTFE). The polymerlayer adjacent to the lumen of the tube frame may be coated with alubricous material.

The tube frame can be covered by an outer jacket, and the outer jacketmay be coated with a lubricious material.

The proximal segment of the tube frame may have a less axial flexibilitythan the distal segment of the tube frame.

The push member can have a cross-sectional width ranging from about 0.25mm to about 2.5 mm. The push member may have a cross-sectional widthranging from about 0.25 mm to about 0.76 mm. The push member can beconstructed from a hypotube having an inner lumen. The push member candefine a substantially rectangular cross section along a length. Thelength of the tube frame can range from about 5 cm to about 150 cm, oralternatively, from about 50 cm to 100 cm.

The tube frame may include a plurality of protrusions which extend fromthe proximal end of the tube frame and/or a plurality of protrusionswhich extend from the distal end of the tube frame. The guide catheterextension may include a flare coupled to the protrusions on the proximalend of the tube frame, wherein the flare is constructed from a polymer.A catheter tip can be coupled to the protrusions on the distal end ofthe tube frame, wherein the catheter tip is constructed from a polymer.The polymer can be impregnated with a radiopaque material.

The tube frame can be constructed from nitinol or spring steel.

Two cuts may be positioned within the tube frame, on either side of thetongue element, each cut running substantially parallel with thelongitudinal axis of the tube. Each of the cuts may terminate in theproximal segment of the tube frame at a keyhole.

The present disclosure provides a guide catheter extension, comprising:a push member having a proximal end and a distal end; and a tube framecoupled to the distal end of the push member, the tube frame defining alumen, having a diameter sufficient to receive an interventionalvascular device therethrough, an inner wall, wherein the tube frameincludes a distal segment having a plurality of rings, wherein each ofthe rings are coupled to one another by a plurality of connection and atongue extending from the proximal segment of the tube, wherein thetongue is coupled to the push member.

Connections between adjacent rings of the plurality of connections maybe axially aligned. Connections between adjacent of the plurality ofconnections may be angularly offset from one another at an angle rangingfrom about 5 degrees and to about 180 degrees. The plurality ofconnections may form a helical pattern along the distal segment of thetube frame.

A polymer liner may be disposed within the lumen and extending throughthe plurality of interconnected rings. The polymer liner can include atleast two polymer layers, wherein each polymer layer has a differentglass transition temperature and wherein the polymer layer adjacent tothe inner wall of the tube frame has a lower glass transitiontemperature (melt temperature) than the polymer layer adjacent to thelumen.

The guide catheter extension can include an outer polymer jacketcovering at least a portion of the plurality of rings, wherein the outerpolymer jacket is not fused to any portion of the plurality of rings.

The present disclosure provides a guide catheter extension, comprising:a push member having a proximal region and a distal region; and a tubeframe coupled to the distal end of the push member, wherein the tubeframe comprises: a tube frame defining a lumen therethrough having adiameter sufficient to receive an interventional cardiology devicetherethrough, wherein the tube frame has an average stiffness betweenapproximately 0.03 N/mm and approximately 0.10 N/mm along a substantiallength thereof. The tube frame is pushable through a curve having aradius of approximately 2.5 mm without kinking. The tube frame may havea wall thickness between approximately 0.0254 mm and approximately 0.254mm. The tube frame may have a wall thickness between approximately0.0635 mm and approximately 0.1143 mm.

The guide catheter extension may include a polymer liner at leastpartially disposed within the lumen of the tube frame, wherein thepolymer liner is partially bonded to the tube frame. The polymer linermay have a wall thickness between approximately 0.00635 mm andapproximately 0.127 mm. The polymer liner can be bonded to the tubeframe at a plurality of discrete locations along the length of the tube,and wherein a width of each bond at each discrete location is betweenapproximately 1 mm and approximately 2 mm.

The guide catheter extension can include a plurality of rings positionedin a distal region of the tube frame, wherein the width of each ring isbetween approximately 50 microns and approximately 200 microns. Eachring may be spaced from an adjacent ring between by approximately 10microns and approximately 300 microns.

The guide catheter extension may include an outer polymer jacketcovering at least a portion of the plurality of interconnected rings,wherein the outer polymer jacket is not fused to any portion of theplurality of interconnected rings, and wherein the outer polymer jackethas a wall thickness between approximately 5 microns and approximately10 microns.

The guide catheter extension may include a tongue element extending fromthe proximal segment of the tube frame, wherein the tongue is coupled tothe push member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a perspective view of an example of a catheter constructedin accordance with the principles of the present disclosure.

FIG. 1 b is a side view of the catheter of FIG. 1 a.

FIG. 1 c is a closer side view of a tube frame of the catheter of FIG. 1a.

FIGS. 2 a-2 h are examples of various cut patterns of a catheterconstructed in accordance with the principles of the present disclosure.

FIG. 3 is another example of a cut pattern of a catheter constructed inaccordance with the principles of the present disclosure.

FIGS. 4 a-4 b depict examples of interconnected ring segmentsconstructed in accordance with the principles of the present disclosure.

FIG. 5 depicts an example of a distal region of a catheter constructedin accordance with the principles of the present disclosure.

FIG. 6 a depicts an example of a distal region of a catheter constructedin accordance with the principles of the present disclosure.

FIGS. 6 b-6 c illustrate examples of the flexibility characteristics ofa catheter constructed in accordance with the principles of the presentdisclosure.

FIG. 7 depicts an example of a distal region of a catheter constructedin accordance with the principles of the present disclosure.

FIGS. 8 a-8 c illustrate examples of cut patterns for a catheterconstructed in accordance with the principles of the present disclosure.

FIGS. 9 a-9 b illustrate examples of cut patterns for a catheterconstructed in accordance with the principles of the present disclosure.

FIG. 10 a is a perspective view of an example of a tube frame of acatheter constructed in accordance with the principles of the presentdisclosure.

FIG. 10 b is an alternative perspective view of the distal tube of FIG.10 a.

FIGS. 11 a-11 b illustrate alternative examples of tube frames of acatheter constructed in accordance with the principles of the presentdisclosure.

FIG. 12 is a side view of an example of a catheter constructed inaccordance with the principles of the present disclosure.

FIG. 13 a-13 b is a perspective view of an example of a push rodcoupling constructed in accordance with the principles of the presentdisclosure.

FIG. 14 is a perspective view of an alternative example of a push membercoupling constructed in accordance with the principles of the presentdisclosure.

FIG. 15 is a perspective view of another alternative example of a pushmember coupling constructed in accordance with the principles of thepresent disclosure.

FIG. 16 is a perspective view of yet another alternative example of apush member coupling constructed in accordance with the principles ofthe present disclosure.

FIG. 17 is a perspective view of still another alternative example of apush member coupling constructed in accordance with the principles ofthe present disclosure.

FIG. 18 is a perspective view of an example of a push member constructedin accordance with the principles of the present disclosure.

FIG. 19 a is a top perspective view of another alternative example of apush member coupling constructed in accordance with the principles ofthe present disclosure.

FIG. 19 b is an underside perspective view of the push member couplingof FIG. 19 a.

FIG. 19 c is a side view of the push member coupling of FIG. 19 a.

FIG. 20 a is a top perspective view of another alternative example of apush member coupling constructed in accordance with the principles ofthe present disclosure.

FIG. 20 b is an underside perspective view of the push member couplingof FIG. 20 a.

FIG. 21 a is a top perspective assembly view of another alternativeexample of a push member coupling constructed in accordance with theprinciples of the present disclosure.

FIG. 21 b is an assembled view of the push member coupling of FIG. 21 a.

FIGS. 21 c-21 d are examples of flexibility patterns constructed inaccordance with the principles of the present disclosure.

FIGS. 22 a-22 f depict examples of axial protrusion configurationsconstructed in accordance with the principles of the present disclosure.

FIGS. 23 a-23 c depict examples of tube frame flares for a catheterconstructed in accordance with the principles of the present disclosure.

FIG. 24 depicts an example of a flare for a catheter constructed inaccordance with the principles of the present disclosure.

FIGS. 25 a-25 c depict another example of a flare for a catheterconstructed in accordance with the principles of the present disclosure.

FIGS. 26 a-26 b depict another example of a flare for a catheterconstructed in accordance with the principles of the present disclosure.

FIGS. 27 a-27 c depict yet another example of a flare for a catheterconstructed in accordance with the principles of the present disclosure.

FIGS. 28 a-28 b depict yet another example of a flare for a catheterconstructed in accordance with the principles of the present disclosure.

FIGS. 29 a-29 d depict a guidewire entering a distal assembly of acatheter constructed in accordance with the principles of the presentdisclosure.

FIG. 30 is an example of a transverse cross-sectional view of thecatheter of FIGS. 1 a -c.

FIG. 31 is a chart illustrating flexibility testing of varying cathetercomponents and assemblies.

FIG. 32 is an illustration of a bend-test configuration for measuringflexibility.

FIGS. 33 a-33 c depicts an example of a fuse pattern for an inner linerof a distal assembly constructed in accordance with the principles ofthe present disclosure.

FIG. 33 d depicts another example of a fuse pattern for an inner linerof a distal assembly constructed in accordance with the principles ofthe present disclosure.

FIG. 34 is a lengthwise cross-sectional view of the distal region of acatheter constructed in accordance with the principles of the presentdisclosure.

FIG. 35 is a lengthwise cross-sectional view of an example of a distaltip for a catheter constructed in accordance with the principles of thepresent disclosure.

FIG. 36 a-36 d depict examples of outer jackets constructed inaccordance with the principles of the present disclosure.

FIG. 37 is a photograph of various catheters navigating curves ofdecreasing radii.

FIGS. 38 a-38 c illustrate an example of use of a catheter constructedin accordance with the principles of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides examples of guide catheter extensiondevices. Referring now to FIGS. 1 a-c , an example of a guide catheterextension 1000 is shown. The guide catheter extension 1000 is sized andconfigured to pass through and extend distally from a guide catheter asdescribed herein. The guide catheter extension 1000 generally includes apush member 1001 coupled to a distal tube frame 1005, and may havesufficient length such that, in use, a proximal region of the guidecatheter extension 1000 is accessible or positioned exterior to apatient (such as at a proximal end or hub of a separate guide catheter),while a distal region of the guide catheter extension 1000 extendsdistally outward from an end of the guide catheter positioned within theanatomy of the patient.

The overall length of the guide catheter extension 1000 may varydepending upon the particular procedure or application being performedand/or a vasculature access point being utilized (e.g., whetherintroduced via a radial artery, femoral artery, contralateral access, orthe like). For example, if the guide catheter extension 1000 is beingused to access a coronary vessel, such as the right and left coronaryarteries, the overall length of the guide catheter extension 1000 may bebetween approximately 110 cm (43.30 inches) and approximately 175 cm(68.89 inches). In a procedure involving access to a peripheral bloodvessel, the overall length of the guide catheter extension 1000 may bebetween approximately 45 cm (17.72 inches) and approximately 300 cm(118.11 inches), with extended lengths being useful for proceduresinvolving brachial or radial artery access points.

The push member 1001 can be made from one or more metallic materials(such as stainless steel), polymers, ceramics, and/or composites thereofproviding sufficient axial loading or pushability to allow a user tomove the guide catheter extension 1000 through an interior of a guidecatheter without having the push member 1001 significantly bend, kink,or otherwise deform and potentially obstruct or damage the guidecatheter, while also providing sufficient flexibility to allow the guidecatheter extension 1000 to navigate various curves and bends of thevasculature while disposed within the guide catheter.

The push member 1001 may include, for example, one or more segments ofhypotube, spiral-cut hypotube, multi-thread cable, interrupted-spiralcut tube, other cut geometries/configurations, or other elongatedmember(s), and may include one or more lumens 1002 therein and/ortherethrough for the passage of one or more wires, devices, fluiddelivery and/or aspiration features, or the like. Alternatively, thepush member 1001 may be constructed without any lumens therein ortherethrough.

The push member 1001 may include a small diameter or cross-sectionalprofile relative to an inner diameter or clearance of the guide catheterto reduce the amount of space within the guide catheter that the pushmember 1001 occupies, thereby allowing one or more other devices,instruments, or otherwise to pass through the guide catheter withminimal interference or obstruction. For example, the push member 1001may have a diameter or cross-sectional width between approximately 0.254mm (0.010 inches) and approximately 2.54 mm (0.100 inches) for use in aguide catheter having an inner diameter of 1.1016-30.48 mm (0.04-1.20inches). In a preferred example, the push member 1001 may have adiameter or cross-sectional width between approximately 0.254 mm (0.010inches) and approximately 0.762 mm (0.030 inches). The push member 1001may have one or more cross-sectional shapes or profiles along itslength, including but not limited to circular, hemi- or semi-circular,square, rectangular, triangular, and/or oval shapes or profiles. Inaddition and/or alternatively, the push member 1001 can comprise aplurality of cut patterns in one or more sections thereof.

The push member 1001 may define a proximal end 1003 and a distal end1004, and may have an overall length constituting the majority of thelength of the guide catheter extension 1000. The length of the pushmember 1001 may be sufficient to enter an incision or patient accesspoint (which may include, for example, a hub, hemostatic valve, and thelike), traverse the vasculature of the patient, and position the tubeframe 1005 in proximity to a desired treatment site while a portion ofthe push member 1001 remains outside the patient and accessible/operableby a physician. The length may vary depending upon the particularprocedure or application being performed and/or a vasculature accesspoint being utilized (e.g., whether introduced via a radial artery,femoral artery, contralateral access, or the like). The push memberand/or other proximal portion of the guide catheter extension 1000 mayinclude a stop feature that prevents a physician from inserting theextension 1000 too far into the guide catheter. For example, the guidecatheter extension 1000 may include a raised protrusion, weld, or othermass that exceeds a diameter or size of a guide catheter, hemostaticvalve, and/or proximal device hub to mechanically prevent theover-insertion of the guide catheter extension 1000.

The tube frame 1005 includes or otherwise defines an outer wall 1007 andan inner wall 1006 enclosing a lumen 1008, a longitudinal axis LA 1009,a proximal segment 1010 and a distal segment 1011. The tube frame 1005has a proximal end 1012 and a distal end 1013 and a length, L, 1014. Thetube frame 1005 has a plurality of cut patterns 1015, 1016 (note, 1015and 1016 represent only two possible embodiments of the various cutpatterns that can be present in the tube frame). The tube frame 1005 hasa tongue element 1017 extending from the proximal segment 1010 of thetube frame 1005, wherein the tongue element 1017 is coupled to the pushmember 1001. In certain embodiments, the tongue element 1017 extendsfrom the proximal end 1012 of the proximal segment 1010.

Both the proximal end 1012 and the distal end 1013 of the tube frame1005 can have protrusions 1019 and 1021, respectively. Flares or capsmay be attached to the protrusions. This embodiment is shown in FIGS. 1a-c with the protrusions 1019 for the proximal end 1012, and the flare1018 on the proximal end and the protrusions 1021 for the distal end1013 with the tip 1023 attached to the protrusions 1021.

A portion of the tube frame 1005 can have a polymer liner 1022 and/orthe outer wall 1007 of the tube frame 1005 can be covered (completely,partially, and/or intermittently) with an outer jacket 1020 (see, e.g.,FIG. 30 ). The proximal end 1012 of the tube frame 1005, the ends of theprotrusions 1019 at the proximal end 1012 of the tube frame 1005, andthe flare 1018 are each oriented perpendicular to the longitudinal axisLA 1009 of a hypothetical plane bisecting the tube frame 1005.

The tube frame 1005 may be constructed from nitinol or stainless steel.For example, the tube frame can be made from metals, polymers, or acombination of polymers and metals. Examples of materials that may beused include stainless steel (SST), nickel titanium (Nitinol), orpolymers. Preferred examples of other metals which may be used include,super elastic nickel titanium, shape memory nickel titanium, Ti—Ni,nickel titanium, approximately, 55-60 wt. % Ni, Ni—Ti—Hf, Ni—Ti—Pd,Ni—Mn—Ga, Stainless Steel (SST) of SAE grade in the 300 to 400 seriese.g., 304, 316, 402, 440, MP35N, and 17-7 precipitation hardened (PH)stainless steel, other spring steel or other high tensile strengthmaterial or other biocompatible metal material. In one preferredembodiment, the material is superelastic or shape memory (e.g., nickeltitanium), while in another preferred embodiment, the material isstainless steel.

The tube frame 1005 can include a superelastic alloy (generally referredto as “a shape-memory alloy”) in its entirety, or in only in selectedsections thereof. Examples of such superelastic alloys include: Elgiloy®and Phynox® spring alloys (Elgiloy® alloy is available from CarpenterTechnology Corporation of Reading Pa.; Phynox® alloy is available fromMetal Imphy of Imphy, France), SAE grade 316 stainless steel and MP35N(Nickel Cobalt) alloys which are available from Carpenter Technologycorporation and Latrobe Steel Company of Latrobe, Pa., and superelasticNitinol which is available from Shape Memory Applications of SantaClara, Calif. U.S. Pat. No. 5,891,191.

Alternatively, the tube frame may be formed from polymers, e.g., includepolyimide, PEEK, nylon, polyurethane, polyethylene terephthalate (PET),latex, HDHMWPE (high density, high molecular weight polyethylene) andthermoplastic elastomers or other polymers with similar mechanicalproperties.

The tube frame 1005 may be made by forming a pipe of a super elasticmetal and then removing the parts of the pipe where the notches or holesare to be formed. The notches, holes or cuts can be formed in the pipeby laser (solid-state, femtosecond laser, or YAG laser, for example),electrical discharge (electrical discharge machining (EDM)), chemicaletching, photo-etching mechanical cutting, or a combined use of any ofthese techniques. U.S. Pat. No. 5,879,381.

The overall length of the tube frame 1005 may vary depending upon theparticular procedure or application being performed and/or a vasculatureaccess point being utilized (e.g., whether introduced via a radialartery, femoral artery, contralateral access, or the like). For example,if the guide catheter extension 1000 is being used to access a coronaryvessel, such as the radial or femoral arteries, the overall length ofthe tube frame 1005 may be between approximately 10.16 cm (4 inches) andapproximately 33.02 cm (13 inches). In a procedure involving access to aperipheral blood vessel, the overall length of the tube frame 1005 maybe between approximately 20.23 cm (8 inches) and approximately 91.44 cm(36 inches).

The tube frame 1005 may be sufficiently sized to receive interventionalcardiology devices and/or instrumentation (such as, for example,treatment catheters, stent delivery and/or recovery devices, aspirationor occlusion treatment devices, etc.) therethrough, while also enablingthe tube frame 1005 to pass through an inner diameter of the guidecatheter.

The tube frame 1005 provides a combination of features contributing tothe function, operability, and performance of the guide extensioncatheter. For example, the tube frame 1005 should provide a desireddegree of structural integrity to prevent the lumen 1008 of the tubeframe 1005 from collapsing during use. The tube frame 1005 alsocontributes to both the pushability and resistance to axial extension orcompression under axial load, while also providing sufficientflexibility to navigate the contours of the anatomy both within andexterior to the guide catheter. To provide such features, the tube frame1005 may be constructed from one or more metals, polymers, and/orcomposites thereof. In one embodiment, the tube frame 1005 may beconstructed from nitinol or spring steel and may have a wall thicknessranging between approximately 0.0254 mm (0.001 inches) and approximately0.254 mm (0.010 inches). In a preferred example, the tube frame 1005 mayhave a wall thickness ranging between approximately 0.0635 mm (0.0025inches) and approximately 0.1143 mm (0.0045 inches).

In one embodiment, the cut patterns of the tube frame 1005 can form aseries or plurality of interrupted spiral cut patterns 15-18. FIGS. 2a-h . The various cut patterns can be distributed at any point along thelength of the tube frame 1005. In another embodiment, the spiral cutpath width includes alternating open or cut portions and uncut portions2005-2007. The spiral pathway width is composed of alternating cut anduncut sections and is angled with respect to a circumference of thetubular portion (in other words, a pitch angle ϕ as shown in FIG. 3 ofless than 90°). Such cut patterns may also be implemented into the pushmember 1001 to provide varying degrees of pushability, flexibility, andoverall operability of the guide catheter extension 1000.

As illustrated in FIG. 3 , each helically-oriented uncut portion has anarcuate extent “α” and each helically-oriented cut portion has anarcuate extent “β”. Angles α and β can be expressed in degrees (whereeach complete helical turn is 360°). The uncut portions can bedistributed such that adjacent uncut portions are not in axial alignment(or “staggered”) with each other along a direction parallel to thelongitudinal axis LA 3009. The uncut portions 3005 on every other turnof the interrupted spiral cut width can be axially aligned. The cutportions are shown as 3003 and 3004, while the spiral pattern is labeled3001 and 3002. FIG. 3 . The pitch angle ϕ and the distribution ofcontinuous or interrupted spiral cut patterns can vary across thelength, L 1014 of the tube frame 1005. The spiral-cut patterns of thetube frame 1005 can be formed from continuous spiral-cut sections,interrupted spiral-cut sections, or a hybrid of both types of spiral-cutpatterns, where the various patterns can be arranged in any order on thetube frame 1005.

The spiral-cut sections provide for a graduated transition in bendingflexibility, as measured by pushability, kink resistance, axial torquetransmission for rotational response, and/or torque to failure. Forexample, the spiral-cut pattern may have a pitch that changes toincrease flexibility in one or more areas of the tube frame 1005. Thepitch of the spiral-cuts can be measured by the distance between pointsat the same radial position in two adjacent threads. In one embodiment,the pitch may increase as the spiral-cut progresses from a proximalposition to the distal end of the catheter. In another embodiment, thepitch may decrease as the spiral-cut progresses from a proximal positionon the catheter to the distal end of the catheter. In his case, thedistal end of the catheter may be more flexible. By adjusting the pitchand the cut as well as the uncut path of the spiral-cuts, thepushability, kink resistance, torque, flexibility and compressionresistance of the tube frame, may be controlled to meet user needs.

The spiral-cut patterns of the tube frame 1005 can be formed fromcontinuous spiral-cut sections, interrupted spiral-cut sections, or ahybrid of both types of spiral-cut patterns, where the various patternscan be arranged in any order on the tube frame 1005. The interrupted cutspiral modules have the ability to maintain a concentric lumen areawhile in a bent configuration, even in sharp bends of small radii. Theability to maintain a concentric lumen of the tube frame 1005 enablessmooth wire movement, in either direction within the tubular lumen,without resulting in a deformation of the lumen. Additionally, usingsuperelastic materials such as Nitinol for the spiral cut segments,allows a segment to bend in tight curves through various vascularpassageways without permanent lumen deformation.

The modulation of flexibility/rigidity across the length of the tubeframe 1005 can be accomplished in a number of ways. For example, byvarying the spiral-cut pattern variables (pitch, interruptions) andtransitioning between spiral-cut patterns the flexibility/rigidity of atube may be controlled. In addition, the spiral-cut pattern allows thecross-sectional diameter of the lumen to be maintained when the tubeframe 1005 is bent or curved. Spiral-cut sections having different cutpatterns may be distributed along the length of the tube. The spiral-cutpatterns may be continuous or discontinuous along the length of themodule. For example, there may be 1, 2, 3, 4, 5, 6, 7, . . . nspiral-cut sections along the length of the tube frame. The spiral-cutsections may be continuous or interrupted. Within each section aconstant cut pattern may be present, but across different sectionswithin a tube frame, the cut patterns may vary, e.g., in terms of pitch.Each section may also contain a variable pitch pattern within theparticular section. Each spiral-cut section may have a constant pitch,e.g., in the range of from about 0.05 mm to about 10 mm, e.g., 0.1 mm,0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm,1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, etc. The pitch may alsovary within each section. The pitches for different spiral-cut sectionsmay be same or different. The orientation or handedness of spiral-cutsections may also vary within the spiral-cut sections. The width of thespiral cuts can vary, e.g., from about 1 micron to about 100 microns.

For an interrupted spiral-cut section, the interrupted spiral patterncan be designed such that each turn or rotation of the spiral includes aspecific number of cuts, Nc (e.g., 1.5, 2.5, 3.5, 4.5, 5.5, etc.). Nccan also be whole numbers, such as 2, 3, 4, 5, n, as well as other realnumbers, such as 2.2, 2.4, 2.7, 3.1, 3.3, etc. At a given Nc, the uncutextent α and the cut extent β can be chosen as α=(360−(β*Nc))/Nc suchthat each rotation has Nc number of repeat patterns each comprising acut portion of extent τ3 adjacent an uncut portion of extent α. Forexample, at Nc=1.5, 2.5, and 3.5, the following table shows examplechoices of various embodiments for α and β.

TABLE I Nc α and β values Nc = 1.5 Nc = 2.5 Nc = 3.5 β (°) α (°) β (°) α(°) β (°) α (°) 230 10 140 4 90 12.13 229 11 139 5 89 13.13 228 12 138 688 14.13 227 13 137 7 87 15.13 226 14 136 8 86 16.13 225 15 135 9 8517.13 224 16 134 10 84 18.13 223 17 133 11 83 19.13 222 18 132 12 8220.13 221 19 131 13 81 21.13 220 20 140 14 80 22.13 219 21 129 15 7923.13 218 22 128 16 78 24.13 217 23 127 17 77 25.13 216 24 126 18 7626.13 215 25 125 19 75 27.13 214 26 124 20 74 28.13 213 27 123 21 7329.13 212 28 122 22 72 30.13 211 29 121 23 71 31.13 210 30 120 24 7032.13 209 31 119 25 69 33.13 208 32 118 26 68 34.13 207 33 117 27 6735.13 206 34 116 28 66 36.13 205 35 115 29 65 37.13

In another embodiment, the cut patterns of the tube frame 1005 comprisea plurality of rings 4001-4016 coupled together by a plurality ofconnections 4018-4024, where the rings 4001-4017 are spaced apart fromeach other by a cut width 4025-4030 (labeled only for illustrationpurposes). FIG. 4 a . The rings are also referred to as “interconnectedrings”. The interconnected rings may include one or more radiopaquemarkers 4050 or other visualization feature that can be viewed throughone or more medical imaging modality during a procedure (e.g.,fluoroscopy, radiography, etc.). Such radiopaque points along the lengthof the plurality of rings and/or tube frame 1005 could be applied byinserting insert one or more radiopaque marker dots or rivets; throughmask coating such as plating or vapor deposition of gold or platinum atdesignated locations; placement of one or more marker rings or bands ofmaterial around the tube frame 1005, which may be coaxially fixed asdescribed herein. In addition and/or alternatively, one or more polymerlayers may be applied to portions of the plurality of rings and/or tubeframe 1005 with radiopaque materials and/or segments embedded therein.

The dimensions of the rings are illustrated as follows. Each ring has awidth 4031. Each ring is spaced from an adjacent ring by a cut width4033. Each connection 4018-4024 or strut has a length 4035 and width4037. FIG. 4 b . Each of these parameters can vary across a plurality ofrings. The pathway around the tube frame 1005 between any two pair ofrings, e.g., 4001/4002, 4002/4003, 4003/4004, 4004/4005, etc., is formedfrom alternating cut section 4027 and uncut sections 4019 (also referredto herein as the connection or strut), each having a set arc length.FIG. 4 b . The dimensions of the cut width, height of the rings, widthand length of the struts can be adjusted to achieve any desiredflexibility or stiffness of the tube frame 1005.

The rings 5001-5007 (selected rings labeled herein only for illustrationpurposes) can be oriented perpendicular (or substantially perpendicular)to the longitudinal axis LA 5008 of the tube frame 5009 and, in apreferred embodiment, the plurality of rings 5001-5007 can be positionedat the distal segment 1011 of the tube frame 1005. FIG. 5 . However, therings can be positioned anywhere along the length L (1014) of the tubeframe 1005.

In certain embodiments, the struts 5014-5016 can form a helical patternover the length of the section of the tube frame having the rings. FIG.5 . In this embodiment, the struts 5014-5016 are distributed on everyadjacent ring, e.g., 5020/5021, 5021/5022 and 5022/5023. The struts onadjacent rings, e.g., 5020/5021, 5021/5022 and 5022/5023, can beangularly offset from each other at an angle ranging from about 5degrees to about 180 degrees (5, 10, 15, 30, 45, 60, 90 and 180degrees).

Alternatively, the struts 6008-6011 (FIG. 6 a ) can be linearly alignedparallel to the longitudinal axis LA 6013 of the tube frame 1005. In theembodiment shown in FIG. 6 , the struts 6008-6011 are spaced on everyother pair of rings. For example, rings 6002 and 6003 are connected bystruts 6008 and rings 6004 and 6005 are connected by strut 6009, butthere is no strut at the same radial position between rings 6003 and6004.

The plurality of rings 6001 (FIG. 6 b ) provide increased flexibilityallowing the distal segment 1011 of the tube frame 1005 containing therings 6001 to navigate curves having radii as small as approximately2.54 mm (0.1 inches). For example, the distal segment containing therings 6001 can bend at a 90-degree angle without compromising orcollapsing the lumen 1008 of the rings 6001 or of the tube frame 1005,consequently avoiding kinking the guide catheter extension during use inincreasingly smaller anatomy or vessels. FIG. 6 c . Although asillustrated here, the rings are distributed only over a portion of theof the tube frame 1005, in other embodiments, the rings can bedistributed over a substantial majority or entire length of the tubeframe 1005.

The number of struts between any two rings can vary from 1-10 with 1 or2 being the preferred number of connections. In other examples, thenumbers of struts may exceed two, but the dimension of the struts may bemodified to maintain the desired degree of flexibility of the guidecatheter extension. The angular offset of the struts, the spacing of therings, and/or the height of each ring may be varied in conjunction withthe overall length of the plurality of the rings to provide the desireddegree of flexibility and pushability of the guide catheter extensionthrough smaller vessels.

Because of the increased flexibility of the rings as compared to theflexibility of either the proximal segments 1010 of the tube frame 1005or other portions of the distal segment 1011, the distal segment 1011may define or otherwise include a transition zone of intermediateflexibility 7001 leading to the plurality of rings 6001 (FIG. 7 ). Forexample, the transition zone 7001 may include cut pattern variations(such as, for example, cut widths, angular orientations, pitch angles,etc.) as compared to that of more proximal sections of the distalsegment 1011 in order to provide a flexibility or average stiffness thatlies between an average stiffness of a proximal region of the distalsegment and an average stiffness of the rings. The transitionalflexibility improves the ability of the guide catheter extension tonavigate tortuous anatomy without compromising or kinking the internallumen, which could otherwise occur with abrupt significant changes instiffness across distal sections of the guide catheter extension.

Another embodiment of the tube frame 1005 cut patterns of the disclosureis shown in FIGS. 8 a-c . The zones can be along any portion of the tubeframe, e.g., in the proximal 1010 or distal 1011 segments, in a singleor multiple segment and may comprise the cut pattern of the entire tubeframe 1005. Each zone includes a plurality of units (or groups) ofradially symmetric, cutout segments that are distributed around thecircumference of the tube in a band or row. A band or row can have 2, 3,4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300,400, 500, 1000 to n units. In FIG. 8 a , seven zones, Zones 1-7 areshown. Units from each of the 7 zones are identified as follows: (i)Zone 1, 8001; (ii) Zone 2, 8002; (iii) Zone 3, 8003; (iv) Zone 4, 8004;(v) Zone 5, 8005; (vi) Zone 6, 8006; and (vii) Zone 7, 8007. Each unitof the cutout portions can include three cutout segments each segmentextending radially from a center point or center of symmetry. The cutoutsegments have a three-fold rotational symmetry, where each cutoutsegment is rotated 120 degrees from an adjacent cutout segment about acenter of symmetry. Within each zone, all of the units of cutoutsegments may have an equal open surface area (i.e., the open surfacearea is the area enclosed by the contour of the segments in a contiguousmanner) as well as an equal cut-pattern perimeter length, the length ofa continuous line traced along the shape of the cutout segment. Acrossdifferent zones, the units of cutout segments may have larger surfaceareas and increased cut-pattern perimeter length in zones when labeledin the figure with higher zone numbers, e.g., the open surface arearanking unit of zone 1<unit of zone 2<unit of zone 3<unit of zone 4<unitof zone 5<unit of zone 6<unit of zone 7 and the cut-pattern perimeterlength ranking is unit of zone 1<unit of zone 2<unit of zone 3<unit ofzone 4<unit of zone 5<unit of zone 6<unit of zone 7. The patterns of thecutout portions having the three-fold rotational symmetry about acentral point of symmetry (center of symmetry) as shown can alsogenerally referred to as the “triplex” pattern or “triplex” cut herein.

The configuration shown provides for a gradually decreasing uncutsurface area coverage along the length of the tube from the Zone 1 toZone 7, enabling the segment of the tube shown in this embodiment tohave a gradually increasing bending flexibility. The 7 zones in FIG. 8 aare shown arranged in sequence, i.e., 1 to 7, only for illustrativepurpose. In other embodiments, the zones containing the units can bearranged in any order along the longitudinal axis to provide any desiredchange of bending flexibility at any point or section along thelongitudinal axis. The tube can be provided with fewer, 1, 2, 3, 4, 5 or6, or more zones, 7, 8, 9, 10, 11, 12, 13, 14 or 15 (higher numbers arealso possible, e.g. 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400,500, 600, 700, 800, 900, 1000 to n different zones). The zones, whichhave different cutout surface areas as well as different cut-patternperimeter lengths, can also be arranged in any order, e.g., zone 1, zone6, zone 7, zone 4, zone 5, zone 3, zone 2, in order to controlflexibility of the tube at any point along the length of the tube.

The spacing between units in a band is shown in FIG. 8 b and isrepresented as dc, where dc is the distance between the center ofsymmetry, Cs, of two adjacent units in the same band. The spacing, dc,is equal within a single band and may be constant across the length ofthe tube in different zones. The spacing between bands within a zone,e.g., zone 1, zone 2 and zone 3, is shown as d1, d2 and d3; d1=d2=d3,where the spacing is measured between the lines, which run through thecenter of symmetry, Cs, of the bands within each zone. The spacingbetween zones, e.g., zone 1-zone 2, d12, zone 2-zone 3, d23 and zone3-zone 4, d34; d12=d23=d34, where the spacing is measured between thelines, 81-86. In one embodiment, the spacing between bands within a zonemay be equal to the spacing of two bands between two different zones,e.g., d1=d2=d3=d12=d23=d34. In other embodiments, the spacing betweenbands within a zone may be greater than or less than the spacing betweenthe bands in two different zones, e.g., d1=d2=d3>d12=d23=d34 ord1=d2=d3<d12=d23=d34.

All cutout segments of the units within a zone can have the sameorientation or are in-phase with respect to the line through the centerof symmetry for each row. The cutout segments in adjacent bands or rowswithin a zone can also have the same orientation or are in-phase withrespect to the line through the center of symmetry for each row. Inother words, the corresponding cutout segments in one unit within a zoneare parallel with the cutout segments in an adjacent unit. The center ofsymmetry, Cs, of units within the same zone, but in adjacent bands isshifted by one unit as shown in

An overview of the transition of the units across zone 1 to zone 7 isshown in FIG. 8 c . The following characteristics apply to thedimensions across the zones. The open surface area of the cutout areasacross the different zones rank orders as: Zone 1<Zone 2<Zone 3<Zone4<Zone 5<Zone 6<Zone 7. The change in either open surface area orcut-pattern perimeter length across multiple zones can be linear,exponential, assume a step-wise or square wave function and beincreasing, decreasing, constant, continuous or discontinuous.

Within any one zone, the cutout segments forming a unit may assume anysymmetrical shape about a center of symmetry, Cs. There may be 1, 2, 3,4, 5, 6, 7, 8, 9, 10 or n cutout segments in a unit. The cutout segmentsmay be continuous or separate. For example, the cutout segment may forma circle or a symmetrical, n-sided polygon, such as a hexagon oroctagon. Different zones may have the same or different symmetricalshapes. The geometric rules, both within a zone as well as across a zoneremain the same in these embodiments as they are for the triplex cutoutsegments described above. Specifically, the units are arranged in aband. A band or row can have 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50,60, 70, 80, 90, 100, 200, 300, 400, 500, 1000 to n units. The spacingbetween units in a band represented as dc, where dc is the distancebetween the center of symmetry, Cs, of two adjacent units in a band, dc,is equal within a single band and may be constant across the length ofthe tube in different zones. The spacing between bands within a zone andacross zones may be equal as well. All cutout segments of the unitswithin a zone can have the same orientation or are in-phase with respectto the line through the center of symmetry for each row or band. Thecutout segments in adjacent bands or rows within a zone can also havethe same orientation or are in-phase with respect to the line throughthe center of symmetry for each row. The center of symmetry, Cs, ofunits within the same zone, but in adjacent bands is shifted. Betweentwo adjacent zones, the units are shifted around the circumference ofthe band such that a straight line can be drawn between the center ofsymmetry for units in adjacent zones. The center of symmetry, Cs, indifferent bands falls along the same line in every other band. In otherwords, the center of symmetry of each unit is positioned at the samepoint on the circumference of the tube frame as the center of symmetryof a second unit in a third, third, fifth, etc. band which is separatedby one band from the first band.

One tube frame 1005 may contain multiple, different zones. For example,the tube can be provided with 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14 or 15 (higher numbers are also possible, e.g. 20, 30, 40, 50, 60, 70,80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 to n differentzones). If a tube frame 5 contains multiple zones, then across differentzones there may be a change in open surface area and cut-patternperimeter length. For example, if the cutout segment is formed in theshape of a hexagon and there are seven zones, a first zone, a secondzone, a third zone, a fourth zone, a fifth zone, a sixth zone and aseventh zone, then the rank order for the open surface area andcut-pattern perimeter length is: unit of first zone<unit of secondzone<unit of third zone<unit of fourth zone<unit of fifth zone<unitsixth zone. If there are equal number of units per zone, then the rankorder applies to zones as well. The change in either open surface areaor cut-pattern perimeter length across multiple different zones can belinear, exponential or assume a step-wise or square wave function and beincreasing, decreasing, constant, continuous or discontinuous.

In embodiments formed from other cutout segments, e.g., circles orn-sided polygons, the width across any uncut portion, may be varied,i.e., the width may be reduced. This reduction in width will result inan increase in the open surface area 1004. By increasing the opensurface area, the uncut surface area within unit in any one zone, theflexibility of that portion composed of such units with increased opensurface area of the cutout segments will increase.

The flexibility of the tube frame 1005 may be controlled at any positionalong the tube frame 1005 by combining one or more zones at variouspositions along the length of the tube. Flexibility of the tube frame1005 is positively correlated with the open surface area. In otherwords, as the open surface area of a cutout segment increases theflexibility of a zone composed of units having the larger cutoutsegments increases. Conversely, flexibility is inversely correlated withthe uncut area; as the uncut surface area increases, flexibilitydecreases.

The total uncut area at any one point on the tube frame 1005 will dependon a number of factors, including the number of bands in each zone andthe dimensions of the cutout segments (the open surface area of aparticular unit). If the number of bands in each zone are constant, thenthe rank order is for the uncut surface area, unit of zone 1>unit ofzone 2>unit of zone 3>unit of zone 4>unit of zone 5>unit of zone 6>unitof zone 7 (in other words, there is a fading of uncut area across zones)and the rank order of flexibility of the tube is zone 1<zone 2<zone3<zone 4<zone 5<zone 6<zone 7 (flexibility is positively correlated withthe open surface area and inversely correlated with the uncut area). Thechange in flexibility across multiple different zones can be linear,exponential or assume a step-wise or square wave function, increasing,decreasing, constant, discontinuous or continuous.

By using different zone patterns along the shaft length, flexibility canbe increased or decreased along the shaft length, as well as othercharacteristics of the tube, such as torque, flexibility, pushability,resistance to axial compression and stretch, maintaining lumen diameterand kink resistance.

According to embodiments of the present disclosure, a tube frame 1005can include a plurality of different cut patterns along lengths thereofthat provide varying degrees of stiffness. For example, as shown in FIG.9 a , the tube frame 1005 includes a first section 9001 havinginterrupted or discontinuous spiral cuts interspersed with uncutsections, which provides an average stiffness for that section between0.002-0.004 N/mm, with a preferred embodiment having a stiffness of0.003 N/mm; a second section 9002 that contains a continuous spiralpattern described above, which provides an average stiffness for thatsection between 0.001-0.003 N/mm, with a preferred embodiment having astiffness of 0.002 N/mm; and a third section 9003 that includes one ormore zones and patterns described above and illustrated in FIGS. 8 a-8 c, which provides an average stiffness for that section between0.002-0.004 N/mm, with a preferred embodiment having a stiffness of0.003 N/mm. The tube frame 1005 may further include section 9004, whichmay include a plurality of interconnected rings as described hereinwhich may provide an average stiffness for that section between0.005-0.016 N/mm. The spiral cut section may include severalsub-sections that may have different spiral parameters, such as cutwidths, gaps, pitches, etc., such that the bending flexibility along thespiral cut section can vary longitudinally as desired. Any combinationof the cut patterns described herein may be used in the tube frame 1005.

Now referring to the example shown in FIG. 9 b , the tube frame 1005 mayalso include one or more solid, uncut sections 9005 a, 9005 b spanningthe length of the tube frame 1005. The uncut sections 9005 a, 9005 b maybe situated between two different (or the same) cut patterns, includingthe interrupted spiral cut sections 9001 a-c, and/or interspersedbetween one or more segments having spiral cuts, interconnected rings,or other patterns, such as those shown in FIG. 9 a or as otherwisedescribed herein.

The tube frame 1005 may be coupled to the push member 1001 in a varietyof different ways. For example, as shown in FIGS. 10 a-b , the tubeframe 1005 may define or include a tongue element 1017 that extendsproximally from a proximal segment of the tube frame 1005. The tongue1017 may be unitary with and be formed from the same materialcomposition as the tube frame 1005. A distal end or region of the tongue1103 may be positioned distally to the proximal opening of the tubeframe 1005/lumen 1008, while a proximal end or region 1105 of the tongueelement 1005 extends proximally past the proximal opening of the tubeframe 1005. FIG. 10 b . The tongue element 1017 can be recessed oroffset longitudinally along the tube frame 1005 in relation to theproximal opening of the lumen 1008. The tongue element 1017 and/or theproximal segment 1010 of tube frame 1005 may include one or more cuts orspaces 1101 adjacent to the tongue element 1005 to allow the tongueelement 1005 to pivot and/or cantilever to a degree with respect to theremainder of the tube frame 1005. FIGS. 10 a-b . The cuts or spaces 1101may connect to or otherwise include one or more keyholes 1102 tofacilitate such cantilever movement and reduce the risk of materialfailure at the deflection point of the tongue. FIG. 10 b . Suchcantilever or pivot movement will thus be oriented about the recesseddistal end of the tongue element 1017, which can be supported by othercomponents described herein, and reduce the likelihood of materialfatigue and/or cyclic loading failure of the tongue element 1017 duringuse of the guide catheter extension.

The distal region 1103 on the tongue element 1017 may assume a varietyof different shapes. In one embodiment, the distal region 1103 assumes agenerally trapezoidal shape. FIG. 11 a . In this embodiment, the cuts orspaces 1101 are angularly offset with respect to the longitudinal axisLA 1009 of the tube frame 1005. The embodiment where the distal region1003 is generally rectangular is shown in FIG. 10 b . In thisembodiment, the cuts 1101 are shown as generally parallel tolongitudinal axis, LA 1009 of the tube frame 1005. In a thirdembodiment, the distal region 1103 of the tongue element 1017 is flushwith the proximal end 1012 of the tube frame 1005. FIG. 11 b.

The tongue element 1017 may be angled with respect to the longitudinalaxis, LA 1009. FIG. 12 . For example, as shown in FIG. 12 , the tongue14 extends towards an inner wall 103 of a surrounding guide catheter“GC” (1201), thereby decreasing any obstruction or cross-sectionalobstacle that the tongue element 1017 may impose in more proximalregions of the tube frame 1017 where additional devices, instruments, orthe like may be positioned. The angle of deflection θ 1202 of the tongueelement 1017 may vary to accommodate particular applications and/orguide catheter dimensions. In one example, the angle between the tongueelement 1017 and the longitudinal axis LA 1009 may be approximately 10degrees. Other embodiments of the angle of deflection can range fromapproximately 5 degrees to 35 degrees.

The tongue element 1017 may be sized and/or shaped to matably couplewith a portion of the push member 1001. For example, as shown in FIGS.13 a-b , the tongue element 1017 may have a substantially rectangularcross section 1301 that is positioned within a correspondingly-shapedslot of the push member 1001. The slot of the push member 1001 may beformed, for example, by flattening a portion 1301 of the otherwisesubstantially rounded tube 1302 that constitutes a portion of the pushmember 1001. Other shapes and cross-sectional profiles may beimplemented to couple the tube frame 1005 to the push member 1001, andthe coupling may be achieved and/or secured by any bonding method,including, crimping, swaging, staking, adhesive bonding, welding,brazing and/or soldering.

Now referring to FIG. 14 , another example of an interconnection betweenthe tube frame 1055 and push member 1001 is shown. In this example, anintermediate coupling member 1401, such as a wire, shim, rod, or thelike, couples to the tongue element 1402 of the tube frame 1005 andextends proximally to couple to the push member 1001. In this example,the intermediate coupling member 1401 may slide over or otherwise attachto the tongue 1402 which may have a shorter length when compared to theexamples of the tongue element 1017. The intermediate coupling member1401 is matably connected 1403 to the push member 1001 at an oppositeend.

In another example, the intermediate coupling member 1401 may couple toor be positioned within an aperture or opening 1501 defined by the tubeframe 1005. For example, as shown in FIG. 15 , the tube frame 1005defines a keyhole opening 1501 instead of a tongue element 1017, and theintermediate coupling member 1401 is positioned within the keyholeopening 1501. The keyhole opening 1501 in the tube frame 1005 may havevarying shapes and sizes to accommodate the intermediate coupling member1401 and facilitate coupling thereto. For example, FIG. 16 illustratesan example of a substantially rectangular opening 1603. The intermediatecoupling member 1401 may be secured in-place with the application of anadhesive, weld, fuse, or other bonding modality, 1601, 1602. Nowreferring to FIG. 17 , in addition and/or alternatively to suchcoupling, a cap 1702 may be positioned over a portion of theintermediate coupling member 1401 to enclose and secure the intermediatecoupling member 1401 to the tube frame 1005, once again employing one ormore applications of an adhesive, weld, fuse, or other bonding modalitybetween the cap 1702, intermediate coupling member 1401, and the tubeframe 1005.

In another example, the push member 1001 may be directly coupled to anaperture or opening defined by the tube frame 5, such as those shown inFIGS. 16-17 . In another embodiment, the push member 1001 may define anelongate portion or segment 1801 that couples directly to the apertureor opening defined by the tube frame 1005. The push member 1001 may thenbe secured directly to the tube frame 1005 by employing one or moreapplications of an adhesive, weld, fuse, or other bonding modality.

In another example, as shown in FIGS. 19 a-b , a length of the pushmember 1001 may overlap with a length of the tongue element 1017 and/orthe intermediate coupling member 1401 to increase the surface areabetween the two components for bonding or other attachment. The pushmember 1001 may further define or include a skive portion 1901 thatreceives a tapered or cut portion 1902 of the tongue element 1017 and/orthe intermediate coupling member 1401. In an alternative example, asshown in FIGS. 1 a and 23 a, the push member 1001 overlaps the tongueelement 1017 and is bonded through and adhesive or weld 1050 to securethe components together.

Now referring to FIGS. 20 a-b , a wire 2100 may be coupled to andoverlap each of the push member 1001 and the tongue element 1017 and/orthe intermediate coupling member 1401 to increase the stability andstrength of the attached assembly. The wire 2100 may be bonded orotherwise coupled to each of the push member 1001 and the tongue element1017 and/or the intermediate coupling member 1401 by welding, adhesive,or other manufacturing process. The tongue element 1017 and/or theintermediate coupling member 1401 may also include a cutdown or taperedsection 2101 that extends into an internal cavity or opening of the pushmember. FIG. 20 c.

Another example of an interconnection between the tube frame 1005 andpush member 1001 is illustrated in FIGS. 21 a-d . In this example, thepush member 1001 includes a keyhole 2102 sized and shaped to receive acorresponding, complementary keyhole cutdown region 2103 of the tongueelement 1017 and/or the intermediate coupling member 1401, as well asoverlapping a length of the push member 1001 with a length of the tongueelement 1017 and/or the intermediate coupling member 1401 to increasethe surface area between the components for bonding or other attachment.

The tongue element 1017, the intermediate coupling member 1401, and/orthe portion of the push member 1001 coupled to the tube frame 1005 mayinclude one or more features, dimensions, geometries, and/or profiles tofacilitate flexibility in one or more planes of motion, therebyimproving and/or contributing to the overall flexibility of the guideextension catheter. Examples of such features are shown in FIGS. 21 c-d, including one or more cutouts, slots, or curved portions to provideflexion or bending in side-to-side and/or up-and-down directions. Otherimplementations or combinations of such features may be employed toprovide a desired degree or range of bending.

The tube frame 1005 may include one or more axially-oriented protrusions1019 extending from the distal 1013 and/or proximal 1012 ends of thetube frame 1005 that provide for or can facilitate attachment of one ormore components or layered materials, as described further herein. FIGS.22 a-f . In certain embodiments, the protrusions 1019 may be generallyparallel with the longitudinal axis LA 1009 of the tube frame 1005.Alternatively, the distal 1012 and/or proximal ends 1013 of the tubeframe 1005 may be flush or flat, i.e., perpendicular with respect to thelongitudinal axis 1009. FIG. 22 a . For example, protrusions 1019 may bemade from a plurality of closed, curvilinear elements which can besinusoidal or generally wave-form (meandering) in shape. FIG. 22 a.

The protrusions 1019 may be laser cut or otherwise manufactured directlyfrom the wall of the tube frame 1005, or otherwise assembled or coupledto the tube frame 1005 such that the protrusions 1019 sharesubstantially the same inner 2201 and outer diameter 2202 dimensionswith the tube frame 1005 (inner dimensions 2203 of the lumen 1008 andouter dimensions 2204 of the tube frame 1005). For example, as shown inFIGS. 22 a-b , the protrusions 1019 may include a plurality ofcurvilinear projections in a crown-like configuration that substantiallycircumscribe an end or opening to the lumen of the tube frame 1005. Thecurvilinear protrusions each include an inner aperture or opening 2205therein. FIGS. 22 a -b.

In another example, the protrusions 1019 may each include asubstantially keyhole-like shape, as shown in FIGS. 22 c-d . The keyholeprotrusions 1019 may generally include a substantially rectangularportion coupled to a substantially circular or curvilinear portion at anend thereof, where the substantially circular or curvilinear portion hasa diameter larger than a width of the substantially rectangular portion.In another example, the protrusions 1019 may each include asubstantially rounded rectangular shape, as shown in FIGS. 22 e-f . Theprotrusions 1019 may generally include a substantially rectangularportion coupled to a substantially semi-circular or curvilinear portionat an end thereof, where the substantially semi-circular or curvilinearportion has a diameter substantially the same as a width of thesubstantially rectangular portion.

The proximal end 1012 of the tube frame 1005 may include a flare orflange 1018 (FIG. 1 b ). The flare or flange 1019 can be used to closeor reduce the gap between the tube frame 1005 of the guide catheter1201. FIG. 23 a . The guide catheter (GC) 1201 encloses the guidecatheter extension, as well as provide a guiding, angled surface todirect wires, instruments, and/or other devices being inserted androuted through the guide catheter extension (such as a treatmentcatheter or stent delivery device) into the proximal opening 2302 andinto the lumen 1008 of the tube frame 1005. The flare 1019 may thus besubstantially coaxial with the longitudinal axis LA 1009 of the tubeframe 1005 and the lumen 1008 therethrough and may extend proximallyfrom a proximal end 1012 of the tube frame 1005 to the distal end 1013.In the embodiment shown, the flare or flange 1018 extends radiallyoutwardly from the proximal opening 2302 and lumen 1008 of the tubeframe 1005 and has a greater outer diameter than the outer diameter ofthe tube frame 1005. The flare or flange 1019 can substantially close orseal any gap 2301 formed between the guide catheter 1201 and the tubeframe 1005. The cross-sectional area of the flare or flange 1018 cantaper or be thinner at the point on the flare 2303 not attached to theaxial protrusions 1021. Functionally, this section of the flare orflange 2305 can act as a “wiper blade” which can be in contact with theguide catheter 1201. This decrease in cross-sectional area across theflare or flange 1018 from the area in contact with the axial protrusionsto the area not in contact will result in an increasing flexibility orability to bend of the flare or flange 1018 at the area or section 2305not in contact with the axial protrusions. This flexibility allows theflare or flange 1018 to accommodate catheters of different diameterwhile maintaining a seal between the guide catheter 1201 and the tubeframe 1005. For example, this type of construction enables the guidecatheter extension to be used to inject contrast media into a targetsite in the patient's vasculature without leakage from the distal end ofthe guide catheter extension, as well as facilitate efficient aspirationthrough the lumen 1008 of the tube frame 1005, rather than throughinterstitial spacing or gaps between the tube frame 1005 and the guidecatheter 1201.

The flare or flange 1018 can be made from one or more elastic polymericmaterials, preferably rubbery material with good lubricity, such asPEBA, PTFE, silicone or other fluoropolymers. The flare or flange 1018may also be radiopaque, which may be achieved by utilizing atungsten-filled or bismuth-filled polymer, such as PBAX®. The thicknessof the flare or flange 1018 can be selected to ensure the flare orflange 1018 has sufficient pliability to allow the guide catheterextension to move axially within the guide catheter 1201 withoutsignificantly hampering its maneuverability. For example, the thicknessof the flare 120 can be about 0.05 mm (0.0019 inches) to about 1 mm(0.039 inches), or about 0.2 mm (0.0078 inches) to about 0.5 mm (0.0196inches).

The flare or flange 1018 can be made as a separate piece and adhered toa proximal end 1012 of the tube frame 1005, including adherence orcoupling of the flare or flange 1018 to the protrusions 1019 (as shownin FIGS. 1 a-c ). In such examples, the flare or flange 1018 may befused or melted onto the protrusions 1019, and the protrusions 1019 mayresist axial separation of the flare or flange 1018 through the geometryand/or aperture/opening features of the protrusions 1019. In analternative example, the flare or flange 1018 may be constructed orformed as an extension of an inner lining or outer jacket of the guidecatheter 1201. The end of the flare or flange 1018 may be substantiallyperpendicular or perpendicular, i.e., not in a skived configuration,with respect to the longitudinal axis LA 1008 of the tube frame 1005.See, e.g., FIG. 1 b.

The flare or flange 1018 can further provide structural support to thetongue element 1017 and/or the intermediary coupling member 1401 bybeing partially fused to and/or having a portion of the flare or flangepositioned against an underside of the tongue element 1017 and/orintermediary coupling member 1401. The flare or flange 1018 can thussupport against or restrain excessive deflection and/or material failureof the tongue element 1017 and/or intermediary coupling member 1401 whenthe guide catheter is in use.

The flare or flange 1018 may include a substantially uniformcircumferential profile. Alternative shapes and profiles of the flare orflange 1018 may also be utilized to facilitate both sealing of thecatheter to the inner wall of the external guide catheter, as well asaiding reception of the guidewire into the lumen of the distal tube. Forexample, as shown in FIG. 24 , the flare or flange 1018 may have anasymmetrical protruding section 2501 extending further outward from aremainder of the flare or flange 1018. The protruding section may bepositioned on the “top” of the device (e.g., substantially opposite thetongue element 1017 or intermediate coupling member 1401. FIG. 24 . InFIGS. 25 a-c , another example of the flare or flange 1018 is shownhaving two protruding sections 2601 positioned opposite each other. InFIGS. 26 a-b , another example of the flare or flange 1018 is shownhaving four protruding sections 2701 positioned approximatelyequidistant form one another around the circumference of the flare. InFIGS. 27 a-c , another example of the flare or flange 1018 is shownhaving a plurality of protruding sections 2801 positioned around thecircumference of the flare or flange 1018.

In one embodiment, these protruding sections 2801 are formed from samematerials as the tube frame 1005 by cutting a plurality of protrudingsections 2901. The flare or flange 1018 can then enclose the pluralityof protruding sections 2901. FIGS. 28 a -b.

As stated above, the flare or flange 1018 aids in directing a guidewire3001 and/or other instruments or devices passed through the externalguiding catheter into the lumen 1008 of the tube frame 1005. Forexample, as shown in FIGS. 29 a-c , a guidewire (GW) 3001 may beadvanced through a proximal portion of the guide catheter (GC) 3001towards the tube frame 1005 of the guide catheter extension. If theguidewire 122 is off-center or otherwise meandering through the lumen1008 of the guide catheter (GC) 1201 when it comes into contact with theflare or flange 1018, the geometry and pliability of the flare or flange1018 directs the guidewire (GW) 3001 into the lumen 1008 of the tubeframe 1005 without damaging the guidewire 3001, as shown in FIGS. 29 a-d. Once passed the threshold of the lumen 1008, the guidewire (GW) 3001can be pushed through the remainder of the tube frame 1005 towards thedistal end 1013 of the tube frame 1005 and out towards the anatomy to betraversed. FIGS. 29 a -d.

Guidewires are typically comparatively thin, having a diameter in theorder of about 0.254 mm to 0.457 mm. Guidewires (GW) are capable oftransmitting rotation from the proximal end of the guidewire to thedistal end of the guidewire. This transmission allows the physician tocontrollably steer the guidewire through the branches of the patient'sarteries and manipulate the catheter to the intended target site in thecoronary artery. Additionally, the distal end of the guidewire should besufficiently flexible to allow the distal portion of the guidewire topass through sharply curved, tortuous coronary anatomy.

Guidewires are well known in the art and the appropriate choice of aguidewire for use the catheter of the present disclosure can be made bya medical professional, such as an interventional cardiologist orinterventional radiologist. Among the common guidewire (GW)configurations used in angioplasty is the type of guidewire illustratedin U.S. Pat. No. 4,545,390. Such a wire includes an elongate flexibleshaft, typically formed from stainless steel, having a tapered distalportion and a helical coil mounted to and about the tapered distalportion. The generally tapering distal portion of the shaft acts as acore for the coil and results in a guidewire (GW) having a distalportion of increasing flexibility that is adapted to follow the contoursof the vascular anatomy while still being capable of transmittingrotation from the proximal end of the guidewire to the distal end sothat the physician can controllably steer the guidewire (GW) through thepatient's blood vessels. The characteristics of the guidewire areaffected significantly by the details of construction as the distal tipof the guidewire. For example, in one type of tip construction, thetapering core wire extends fully through the helical coil to the distaltip of the coil and can be attached directly to a smoothly rounded tipweld at the distal tip of the coil. Such a construction typicallyresults in a relatively stiff tip suited particularly for use whenattempting to push the guidewire through a tight area of stenosis. Inaddition to a high degree of column strength, such a tip also displaysexcellent torsional characteristics.

A liner 3101 may comprise one or more polymers arranged in layers toform a tube. For example, the liner 3101 may form a tube comprising twodifferent materials, 3102, 3103, each with a different crystalline meltor melt temperature. The liner 3101 may be constructed from one or morepolymers. Some examples of suitable polymers may includepolytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE),fluorinated ethylene propylene (FEP), polyoxymethylene (POM, forexample, DELRIN available from DuPont), polyether block ester,polyurethane (for example, Polyurethane 85A), polypropylene (PP),polyvinylchloride (PVC), polyether-ester (for example, ARNITEL availablefrom DSM Engineering Plastics), ether or ester based copolymers (forexample, butylene/poly(alkylene ether) phthalate and/or other polyesterelastomers such as HYTREL available from DuPont), polyamide (forexample, DURETHAN available from Bayer or CRISTAMID. available from ElfAtochem), elastomeric polyamides, block polyamide/ethers, polyetherblock amide (PEBA, for example available under the trade name PEBAX.),ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE),Marlex high-density polyethylene, Marlex low-density polyethylene,linear low density polyethylene (for example REXELL), polyester,polybutylene terephthalate (PBT), polyethylene terephthalate (PET),polytrimethylene terephthalate, polyethylene naphthalate (PEN),polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI),polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (for example, KEVLAR), polysulfone, nylon,nylon-12 (such as GRILAMID available from EMS American Grilon),perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin,polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS50A), polycarbonates, ionomers, biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like. In some examples, the liner 3101 can beblended with a liquid crystal polymer (LCP).

For example, as shown in FIG. 30 , the liner 3101 may be disposed withinthe lumen 1008 of the tube frame 1005 and extend from the proximal end1012 of the tube frame 1005, adjacent and/or coupled to the flare 1018and/or axial protrusions 1019, down to and/or past the distal end 1013of the tube frame 1005. The liner 3101 may have an overall lengthgreater than the length of the tube frame 1005 such that a portion ofthe liner 3101 extends beyond and out of the distal end of the tubeframe 5, as shown. The liner can form a tube 3103 within the tube frame1005.

The liner 3101 contributes to (and/or not otherwise significantlyimpede) the operability of the tube frame 1005, and the guide catheter1201 overall, to navigate tortuous anatomy having reduced radii ofcurvature, while also complimenting the pushability of the guidecatheter extension both within and partially external to the guidecatheter 1201. To achieve such performance, the liner 3101 may beconstructed from the materials listed above and may include a wallthickness between approximately 0.00635 mm (0.00025 inches) andapproximately 0.127 mm (0.005 inches). In a preferred example, the liner3101 may be constructed from the materials listed above, and may includea wall thickness between approximately 0.00635 mm (0.00025 inches) andapproximately 0.0127 mm (0.0005 inches).

The liner 3103 may be only partially and/or intermittently fused,bonded, or otherwise adhered to the tube frame 5 to further contributeto the overall flexibility and pushability of the guide catheter. Theattachment of the liner 3103 to the inner wall of the tube may include,for example, heat fusing/melting, use of an adhesive, or othermanufacturing processes. The bonding/attachment process may include oneor more intermediary compounds or materials to facilitate or effect theattachment between the liner 3103 and the tube frame 1005. For example,in a device utilizing a liner constructed from PTFE, a PEBAX® powdercoating may be applied between the PTFE liner and the distal tube. Heatmay then be applied to the tube frame 1005 assembly at a temperaturesufficient to melt the PEBAX®, but lower than a temperature required tomelt the PTFE. The melted PEBAX® thus bonds the PTFE liner to the tubeframe 1005 to secure it in place. The fused segment of PEBAX® can beattached as a ring or a point.

When a polymeric liner is completely bonded to a tube frame 1005, therigidity of the fused assembly greatly increases, and flexibility isdecreased due to, at least in part, the change in hardness of the fusedliner resulting from the bonding process. For example, FIG. 31 providesmeasurements from a series of bending tests applied to components andcombinations of tube frame 5 and liner 3103 assemblies. The Y-axis ofthe graph shows the bending force required to bend the subject assemblyor component, while the X-axis refers to the position along the lengthof the subject assembly or component where the force was applied andmeasured. When the liner is fully fused the tube frame 1005 is leastflexible as measured by the 3-point Bend test. The bend tests wereperformed using a setup similar to that illustrated in FIG. 32 , e.g.,by supporting a length L of the tube frame 1005 at two points, thenapplying a force F to the midsection of that length, measuring theresulting deflection, and calculating and calculating a resultingstiffness value. The test fixture used to perform the measurements was aChatillon® LTCM-6 digital motorized force tester.

As shown in the graph of FIG. 31 , a tube frame 1005 without any linerdisposed therein or thereon requires between approximately 0.22N-0.35Nto bend. A tube frame 1005 with an unbonded, unfused liner disposedtherein requires between approximately 0.335N-0.469N to bend. A tubeframe 1005 with a partially bonded liner disposed therein requiresbetween approximately 0.469N-1.088N to bend, depending on the proximityof the bending force to the location where the bonding/fusing is located(e.g., a higher bending force is required in close proximity to a fusepoint, while significantly lower force is needed the further thedistance from the fuse point). A tube frame 1005 with the liner fullyfused to a tube frame requires between approximately 1.1N-1.405N to bendthe assembly, which is close to 3× the bending force compared to thelower end of the bending force required for the partially fusedassembly. As a result, a partially fused liner construct can provideflexibility and operable performance that is several times greater thantraditional, fully-fused liner constructs.

For example, the liner 3203 may be intermittently or partially fused,bonded, and/or otherwise adhered to the tube frame 5 using differentpatterns, spacing, and/or shape(s) of the fuse points or segments thatbond the liner 3203 to the tube frame 1005. Such patterns, spacing,dimensions, and/or shapes may be varied in conjunction with othervariable features of the distal assembly (e.g., material selection, wallthickness, cut patterns, etc.) to provide the overall desiredpushability and flexibility of the guide catheter extension.

For example, coupling of the liner 3203 to the tube frame 1005, mayinclude the creation or implementation of one or more fused segments3301, each having a substantially ring-like or circumferential profile,as shown in FIG. 33 a . Each substantially circumferential fused segment3203 may have a width between approximately 1 mm (0.0393 inches) andapproximately 2.54 cm (1 inch). A plurality of substantiallycircumferential fused segments may be employed along the length of thedistal assembly, where sequential substantially circumferential fusedsegments are spaced apart by between approximately 1 mm (0.0393 inches)and approximately 2.54 cm (1 inch). FIGS. 33 b-c . In another example,the liner 3203 may be coupled to the tube frame 5 at three locations—ator near the proximal 10 and distal ends 11 of the tube frame 5, and ator near the approximate midpoint of the tube frame 5.

In a preferred example, each fused segment 3301 may have a width betweenapproximately 1 mm (0.0393 inches) and approximately 2 mm (0.0787inches), and sequential fused segments may be spaced apart no less thanapproximately 12.7 mm (0.5 inches).

In another example, a continuous, substantially continuous, and/orinterrupted spiral pattern may be implemented for the fused segment(s)3301. FIG. 33 d . Such a fuse pattern could be achieved, for example, byrotating and pulling the tube frame 1005 across a heating point, thusproviding the spiral pattern. The width, pitch, and/or spacing of thespiral pattern may be similar to the dimensions and examples providedabove. A fusing pattern may be used such as a dashed line or interruptedspiral bonding points

Alternatively, the liner 3203 may be fused to one or more segmentsproximal and/or distally to the rings, but otherwise ‘float’ unboundwithin the length of the lumen 1008 passing through the rings. The outerjacket 1020, discussed below, may similarly be fused to one or moresegments proximal and/or distally to the rings, but otherwise ‘float’unbound across the exterior of the length of the rings.

The length of the tube frame 1005 can vary. For example, the length ofthe tube frame can range from about 15 cm to about 35 cm, about 10 cm toabout 25 cm, about 20 cm to about 45 cm, about 30 cm to about 50 cm,about 5 cm to about 15 cm or about 1-5 cm.

Depending on the material as well as the structural requirements interms of flexibility, the wall thickness of the tube frame 5 at anypoint can vary, e.g., from about 0.05 mm to 2 mm, e.g., 0.05 mm to about1 mm, about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8mm, 0.9 mm, 1.0 mm, etc. The inner diameter of the tube can vary, e.g.,from about 0.1 mm to about 2 mm, or from about 0.25 mm to about 1 mm,e.g., about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, about 2 mm,about 2.5 mm, about 3 mm thickness. The outer diameter of the tube frame5 can also vary, e.g., from about 0.2 mm to about 3 mm, e.g., includingabout 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm,about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, about 1.1 mm,about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm,about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2.0 mm, about 2.5 mm,about 3 mm thickness. The wall thickness of the tube frame 5 wall, theinner diameter and the outer diameter can each be constant throughoutthe length of the tube frame 5 or vary along the length of the tubeframe 5.

In addition, the inner walls, i.e., lumen, of the tube can be coatedwith a liner 3201 that both protects the tube frame 1005 and facilitatestransport of additional tools devices such as guidewires and balloonsthrough the tubes of the catheter to distal locations. The liner 3201can extend along a portion of the tube or can extend throughout theentire length of the tube. The liner 3201 can form a partial or completetube.

The distal end 1013 of the tube frame 1005 may further include acatheter tip 1023 to aid in navigating both the inside of the externalguide catheter as well as the anatomy to be accessed by the guidecatheter extension. The catheter tip 1023 may have a rounded and/ortapered atraumatic profile and be coupled to the distal end of the tubeframe 5 such that the catheter tip 1023 is substantially coaxially withthe longitudinal axis LA of the tube frame 1005 and the lumen 1008therethrough. The catheter tip 1023 may be secured to tube frame 1005 byfusing the catheter tip 1023 with the inner wall 1006, the outer jacket3401, the liner 3201, and/or the axial protrusions 1021 extending fromthe distal end 1013 of the tube frame 1005. FIG. 34 . In the exampleshown in FIG. 34 , the catheter tip 1023 is ‘sandwiched’ betweenportions of the liner 3201 and the outer jacket 3401, and is furtherfused to portions of the axial protrusions 1021.

The catheter tip 1023 may be constructed from a relatively soft orpliable material, such as PEBAX®. The tip may be radiopaque, which maybe achieved through the inclusion or infusion of tungsten, bismuth,and/or barium sulphate into the tip material, or as otherwise set forthherein.

Alternatively, at least two radiopaque markers, such as bands whichpractically or completely enclose the tube frame 1005 can be positionedalong the tube frame 1005 for aiding radiographic visualization. Themarkers can include a radiopaque material, such as metallic platinum,platinum-iridium, Ta, gold, etc., in the form of wire coil or band,vapor deposition deposits, as well as radiopaque powders or fillers,e.g., barium sulfate, bismuth trioxide, bismuth sub carbonate, etc.,embedded or encapsulated in a polymer matrix. Alternatively, the markerscan be made from radiopaque polymers, such as radiopaque polyurethane.

In another embodiment, the catheter tip has a proximal end 3501 and adistal end 3502, where the distal end 3502 forms an inwardly bendingcurve forming an opening that has a diameter Dt smaller than that of thelumen 1008 of the tube frame 1005. The catheter tip 3501 near the distalend 3502 can include a number of cuts to make the distal tip morebendable, i.e., smaller “nose cone” like end in order to minimize traumaof the blood vessel wall when the distal tip is being advanced into apatient's vasculature.

In another type of catheter tip construction, the tapered core wireterminates short of the tip weld. It is common in such a construction toattach a very thin metallic ribbon at one (proximal) end to the corewire and at its other (distal) end to the tip weld. The ribbon serves asa safety element to maintain the connection between the core wire andthe distal tip weld in the event of coil breakage. It also serves toretain a bend formed in the ribbon to maintain the tip in a bentconfiguration as is desirable when manipulating and steering theguidewire. Additionally, by terminating the core wire short of the tipweld, the segment of the helical coil between the distal end of the corewire and the tip weld is very flexible and floppy. The floppy tip isdesirable in situations where the vasculature is highly tortuous and inwhich the guidewire must be capable of conforming to and following thetortuous anatomy with minimal trauma to the blood vessel. In anothertype of tip construction, the distal-most segment of the core wire ishammered flat (flat-dropped) so as to serve the same function as theshaping ribbon but as an integral unitary piece with the core wire. Thetip of the flat dropped segment is attached to the tip weld.

The outer jacket 1020 may be constructed from nylon, polyether blockamide, PTFE, FEP, PFA, PET, PEEK, etc., and/or combinations orcomposites thereof. The outer jacket 125 may have a wall thicknessbetween approximately 0.00508 mm (0.00020 inches) and approximately0.127 mm (0.0050 inches) to minimize any increased outer diameter of theguide catheter 102 as compared to the tube frame 1005 outer diameter. Ina preferred example, the outer jacket 1020 may have a wall thicknessbetween approximately 5 microns (0.00020 inches) and approximately 10microns (0.00040 inches). The outer jacket 1020 may span a length 1014of the tube frame 1005. The outer jacket 1020 provides an atraumatic,protective covering over the rings to eliminate or significantly reduceany trauma or pinching of surrounding tissue when the rings bend tocontour and travel through curvilinear anatomy.

While the outer jacket 1020 illustrated in FIGS. 30, 34 has asubstantially smooth, cylindrical configuration, the outer jacket 1020may include one or more cut patterns or other geometric features tofacilitate, complement, and/or contribute to the overall flexibility ofthe distal assembly. For example, the outer jacket 1020 may include aninterrupted spiral cut pattern therein, as shown in FIG. 36 a .Alternatively, the outer jacket 1020 may include a series of spaced,substantially linear cuts or holes therein, as shown in FIG. 36 b . Inanother example, the outer jacket 1020 may have a substantiallybellows-like configuration, as shown in FIG. 36 c . FIG. 36 dillustrates another example, where the outer jacket 1020 may include awound spiral configuration.

The outer jacket 1020 can be made from a polymer, e.g., by enclosing thetube wall with a co-extruded polymeric tubular structure of single ofmultiple layers and heat shrinking the tubular structure or coating thetube frame 1005 via a dip coating process. The polymer jacket materialcan be nylon, polyether block amide, PTFE (polytetrafluoroethylene), FEP(fluorinated ethylene propylene), PFA (perfluoroalkoxy alkane), PET(polyethylene terephthalate) or PEEK (polyether ether ketone). Further,a portion of the tube frame 5 (or the entire length of guide catheterextension, including the guide catheter) may be coated with ahydrophilic polymer coating to enhance lubricity and trackability.Hydrophilic polymer coatings can include, but are not limited to,polyelectrolyte and/or a non-ionic hydrophilic polymer, where thepolyelectrolyte polymer can include poly(acrylamide-co-acrylic acid)salts, a poly(methacrylamide-co-acrylic acid) salts, apoly(acrylamide-co-methacrylic acid) salts, etc., and the non-ionichydrophilic polymer may be poly(lactams), for examplepolyvinylpyrollidone (PVP), polyurethanes, homo- and copolymers ofacrylic and methacrylic acid, polyvinyl alcohol, polyvinylethers, snapicanhydride based copolymers, polyesters, hydroxypropylcellulose, heparin,dextran, polypeptides, etc. See e.g., U.S. Pat. Nos. 6,458,867 and8,871,869. The coating can be applied by a dip coating process or byspraying the coating onto the tube outer and inner surfaces.

A lubricious coating or film may be added over the outer jacket tofacilitate movement of the catheter through blood vessels. Thelubricious coating can be composed of, for example, silicone or hydrogelpolymers or the like, such as polymer networks of a vinyl polymer,polyalkylene glycols, alkoxypolyethylene glycols or an uncrosslinkedhydrogel, e.g., Polyethylene oxide (PEO).

One or more surfaces of the guide catheter extension may include alubricious, hydrophilic, protective, or other type of coating.Hydrophobic coatings such as fluoropolymers provide a dry lubricitywhich improves guidewire handling and device exchanges. Lubriciouscoatings improve steerability and improve lesion crossing capability.Suitable lubricious polymers may include silicone and the like,hydrophilic polymers such as high-density polyethylene (HDPE),polytetrafluoroethylene (PTFE), polyarylene oxides,polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics,algins, saccharides, caprolactones, other compounds disclosed herein,and the like, and mixtures and combinations thereof. Hydrophilicpolymers may be blended among themselves or with formulated amounts ofwater insoluble compounds (including some polymers) to yield coatingswith suitable lubricity, bonding, and solubility.

The tube frame 1005 (or a portion thereof) may be substantially uniformin diameter across its entire length. Alternatively, the tube frame 1005can have a varying diameter across its length, e.g., a taperedconfiguration.

The tube frame 1005 can have variable flexibility, kinkability, torqueto failure, torqueability, trackability, pushability, crossability, androtational response. A variety of different tests are available fortesting flexibility, kinkability, torque to failure, torqueability,trackability, pushability, crossability, and rotational response.Various standard tests for these properties known in the art aredisclosed in, for example,http://www.protomedlabs.com/medical-device-testing/catheter-testing-functional-performance(retrieved Oct. 8, 2018).

Flexibility is the quality of bending without breaking. The flexibilityof the tube is dependent on the material used, the interrupted spiralpattern, the wall thickness, the inner diameter and the outer diameter,and other variables. Flexibility can be determined by one of thefollowing testing methods. One method of testing flexibility uses aproximal load cell to measure the ability of the device to advance andwithdraw, with no loss of function or damage to the tortuous anatomy,over a specific bend angle. Alternatively, a roller system can be usedto determine the smallest radius of curvature that the device canwithstand without kinking. Additionally, tests can be performed by acantilever beam to measure force and bending angle by calculatingF=[M×(% SR)]/(S×100) with angularity at 50° where F=flexibility, M=totalbending moment, % SR=scale reading average, and S=span length. Anothermethod of testing flexibility is to use one- and four-point bendingtests to evaluate flexibility under displacement control using a ZWICK005 testing machine which detects the force F and the bending deflectionf (https://www.zwick.com/en/universal-testing-machinesh/zwickiline,retrieved Oct. 29, 2018). The highest measured data describes theflexibility as determined by the equation E×I=(F×L³)/(3×f) (Nmm²) whereI=moment of inertia, E=Young modulus, L=bending length, f=bendingdeflection, and F=point force and E×I=flexibility.

Torque to failure or brake is the amount of twisting or rotational forcethe tubular member can withstand before a plastic deformation of thecatheter components, a fracture or break occurs. One method for testingtorque to failure is through the use of proximal and distal torquesensors which measure the amount of torque and the number of revolutionsuntil device failure by rotating the device at a more proximal locationand fixing the distal end while the device is routed through tortuousanatomy. Another testing method for calculating torque to failure is bytesting torque strength immediately following submersion in 37±2° C.water for a set period of time. With a guidewire in place, the devicecan be inserted into a compatible guiding catheter which is constrainedin a two-dimensional shape to replicate access into the coronary anatomyuntil the distal most 10 cm of the catheter is exposed beyond theguiding tip and is attached to a torque gauge to prevent rotation. Theremainder of the catheter body is rotated in 360° increments untildistortion, failure, breaks, fractures, kinks, or other damage occursalong the catheter or at the catheter tip, or for a set number ofrotations.

Torqueability is the amount of torque, or rotation, lost from one end ofthe tube to the other end of the tube when a rotational force is exertedon one end. One method for testing torqueability is by using a proximaland distal torque sensor to measure the amount of torque transmittedthrough the device by rotating the device at a more proximal locationand fixing the distal end while the device is routed through tortuousanatomy. Another method for testing torqueability is by using an arterysimulating device for PTCA training, such as the PTCA trainer, T/N:T001821-2, designed by Shinsuke Nanto, M.D., which simulates a clinicaltortuous path. An indicator attached to the catheter tip and insertedthrough the hole of a dial. The catheter body is connected to a rotator,for example T/N: T001923, and rotated clockwise in 90° increments toabout 1080°. The angle measured by dial attached to the indicator on thecatheter tip is used to calculate the ratio of the angle of rotation ofthe body to the angle of rotation of the tip, which corresponds with theamount of torque lost during rotation.

A method for testing trackability is to use a proximal load cell tomeasure the force to advance the device through a tortuous anatomy withor without the aid of a guiding accessory.

One method for testing pushability is to use a proximal and distal loadcell to measure the amount of force the distal tip of the device seeswhen a known force is being applied to on the proximal end.

A method for testing crossability is to use a proximal load cell tomeasure the ability of the catheter device to advance and withdraw overa specific lesion site without loss of function or damage to thetortuous anatomy. Additionally, a roller system can determine the worstlesion that the device can withstand without damage.

One method for testing rotational response is by using proximal anddistal rotation encoders to measure the amount of rotation transmittedthrough the device by rotating the device at a more proximal locationand keeping the distal end free while the device is routed throughtortuous anatomy.

The features of the guide catheter extension as disclosed and describedherein provide significantly improved performance compared to existingcatheters. The distal assembly, incorporating the features set forthherein, can provide an average stiffness between approximately 0.03 N/mmand approximately 0.10 N/mm along a substantial length thereof, whichprovides improved capabilities compared to existing prior art devices.The unexpected and improved capabilities of the guide catheter extensionoverall, resulting from the combination of the various specificationsset forth herein (e.g., intermittent liner bonding, tube frame 1005 cutpatterns, wall thickness, and other features) are demonstrated by theability of the extension catheter 1000 to traverse narrow curvature thatcannot be traversed by other devices. Moreover, the cut patterns in thetube frame provide improved flexibility while also providing improvedlumen integrity (e.g., the ability to maintain the lumen diameter duringsignificant bending and navigation of tortuous anatomy) compared totraditional braided or coil-reinforced catheters of the prior art.

For example, FIG. 37 is a photograph of 3 different prior art devices(“PA1”, “PA2”, “PA3”) being pushed over a guidewire GW through anidentical curvilinear path having decreasing radii from left-to-right.The stop point SP where each of the prior art devices stops and does notproceed through the path any further under an axial load (i.e., due tokinking, deformation, or otherwise) is circled. In comparison, anexample of the guide catheter extension was pushed over a guidewirethrough the same curvilinear path to successfully reach a stop point SPat a much smaller radii than the prior art devices—radii as small asapproximately 2.54 mm—without kinking or material deformation. Thisdemonstrates the ability of guide catheter extension to traversesmaller, more tortuous anatomy and vasculature than existing devices,thereby allowing for wider application of treatment options andlocations.

The variable flexibility of the sections of the tube frame alsofacilitates surgical procedures in which side-branch access is requiredor where tortuous vasculature is encountered such as in the centralnervous system. Given the ability to use a wide variety of combinationsfrom the base tube's material mechanical properties, the tubingdimensions (OD/ID), wall thickness, cut tubing's mechanical propertiesresulting from the cut pattern along the tube's (material composition,UTS, % Elongation modulus of Elasticity, and other combinations ofmaterial and mechanical properties (UTS, formulas defining cut pitchangle, cut width, helical cut arc length and uncut helical space betweennext helical arc cut), all enable the designer to tailor a variety ofmechanical properties defined throughout the running length of the cuttube. Such resulting properties such as stiffness, flexibility and usingthe shape memory properties define a preset curvilinear shape areprogrammable and changeable.

Additionally, such an induced shape memory form would require a greaterforce to straighten or diminish and maintain via a resistive load forcealong the cut and shape treated portion of the distal tubular segment,to orient the shape set portion of the tube to revert back into astraight linear concentric coaxial configuration, which would enable thecatheter to be advanced to the vascular target.

Such variables assembled together, to create a wide variety ofstructural shape combinations of tubes. These structural shapes caneasily be temporarily diminished inline by advancing the tubes over awire track, e.g., a guidewire, which exhibits mechanical properties ofdeformation that exceed the curvilinear shape's spring constant. Thistemporary deformation enables advancement of the catheter, the tubes,over the guidewire through the vascular anatomy. Simply put, the springconstant of the shaped curve portion is less than that of the wiresegment it is tracking over. Once the retaining guidewire segment'sspring constant is less than that of the set curvilinear shape, the cutshaped tube segment will revert back to its preset shape, unless actedupon by an additional other external forces or vascular confinement.

Such methods may be implemented to access and treat a myriad of varyingconditions and/or diseases in anatomical regions, including, peripheral,cardiovascular, and neurological (e.g., central nervous system) havingminimal or difficult access. For example, complex anatomic variation ofblood vessels is common in the aortic arch, the hepatic arterialconfiguration, gastric arteries, celiac trunk, superior mesenteric,renal arteries, femoral arteries as well as axillary arteries. Kahn etal. Complex arterial patterning in an anatomical donor. TranslationalResearch in Anatomy. 12: 11-19 (2018). The anatomic structure of aparticular vasculature has direct clinical relevance, particularlyduring invasive diagnostic and surgical procedures. Not only can theanatomy of a vascular site vary significantly, but also, the proceduremay require the use of multiple devices, e.g., wires, balloons and guidecatheters. Guide catheter extension devices, such as the devicesdisclosed herein, can provide improved delivery of multipleinterventional devices into such anatomy.

In one example of use, the guide catheter extension 1000 may be used tosupplement and extend the reach of a typical guide catheter toultimately reach and/or treat an anatomical location. For example, asshown in FIG. 38 -c, a typical guide catheter GC 1201 may be passed overa guidewire GW 3001, through the aortic arch into an ostium of acoronary artery, which may have a stenotic lesion for treatment. Oncethe distal end of the guide catheter GC 1201 is seated in the ostium ofthe coronary artery, the guide catheter extension 1000 is passed throughthe interior of the guide catheter GC 1201 and extended distally of thedistal end of the guide catheter GC 1201, deeper into the coronaryartery.

The guidewire GW 3001 may then be pushed past the stenotic lesion orother occlusion. In some instances, the application of force to theguidewire GW 3001 could cause the guide catheter GC 1201 to dislodgefrom the ostium of the coronary artery in cases of a tough stenotic orocclusive lesion. However, the combination of guide catheter GC 1201with the extending guide catheter extension 1000 inserted into theostium provides improved distal anchoring of the devices and alsoprovides stiffer back up support than the external guide catheter GC1201 alone, thereby resisting dislodgement when the guidewire GW 3001 ispassed through the lesion, and further provides improved back up supportto assist in the positioning of a subsequent treating catheter that mayinclude a stent or balloon.

Once the guidewire GW 3001 is pushed past the stenotic or occlusivelesion, a treating catheter (not shown) including a stent, balloon,and/or other treatment or diagnostic components can be passed along theguidewire to treat the lesion.

Such methods may be implemented to access and treat a myriad of varyingconditions and/or diseases in anatomical regions having minimal ordifficult access. For example, complex anatomic variation of bloodvessels is common in the aortic arch, the hepatic arterialconfiguration, gastric arteries, celiac trunk, superior mesenteric,renal arteries, femoral arteries as well as axillary arteries. Kahn etal. Complex arterial patterning in an anatomical donor. TranslationalResearch in Anatomy. 12: 11-19 (2018). The anatomic structure of aparticular vasculature has direct clinical relevance, particularlyduring invasive diagnostic and surgical procedures. Not only can theanatomy of a vascular site vary significantly, but also, the proceduremay require the use of multiple devices, e.g., wires, balloons and guidecatheters. Guide catheter extension devices, such as the devicesdisclosed herein, can provide improved delivery of multipleinterventional devices into such anatomy.

The scope of the present disclosure is not limited by what has beenspecifically shown and described hereinabove. Those skilled in the artwill recognize that there are suitable alternatives to the depictedexamples of configurations, constructions, and dimensions, andmaterials. Moreover, while certain embodiments or figures describedherein may illustrate features not expressly indicated on other figuresor embodiments, it is understood that the features and components of theexamples disclosed herein are not necessarily exclusive of each otherand may be included in a variety of different combinations orconfigurations without departing from the scope and spirit of thedisclosure. The citation and discussion of any references in theapplication is provided merely to clarify the description of the presentdisclosure and is not an admission that any reference is prior art tothe disclosure described herein. All references cited and discussed inthis specification are incorporated herein by reference in theirentirety. While certain embodiments of the present disclosure have beenshown and described, it will be obvious to those skilled in the art thatchanges and modifications may be made without departing from the spiritand scope of the disclosure. The matter set forth in the foregoingdescription and accompanying drawings is offered by way of illustrationonly and not as a limitation.

What is claimed is:
 1. A catheter, comprising: a tube frame having aplurality of cuts therein, the tube frame defining a longitudinal axisand a lumen therethrough, wherein the tube frame is constructed from ametal tube; and a PTFE liner disposed within the lumen, wherein theliner is intermittently bonded to the tube frame along a length thereofby melted polyether block amide powder.
 2. The catheter of claim 1,wherein the PTFE polymer liner that is intermittently bonded to the tubeframe defines a plurality of substantially circumferential fusedsegments spaced along a length of the catheter.
 3. The catheter of claim2, wherein each of the plurality of substantially circumferential fusedsegments is spaced from one another between 1 mm and 2.54 cm.
 4. Thecatheter of claim 2, wherein each of the plurality of substantiallycircumferential fused segments is spaced from one another by at least12.7 mm.
 5. The catheter of claim 2, wherein the plurality ofsubstantially circumferential fused segments constitutes three fusedsegments substantially equally spaced along a length of the catheter. 6.The catheter of claim 2, wherein each of the plurality of substantiallycircumferential fused segments has a width between 1 mm and 2.54 cm. 7.The catheter of claim 2, wherein each of the plurality of substantiallycircumferential fused segments has a width between 1 mm and 2 mm.
 8. Thecatheter of claim 1, wherein the PTFE liner is intermittently bonded tothe tube frame to define a fused segment having a spiral pattern.
 9. Thecatheter of claim 8, wherein the spiral pattern is substantiallyuninterrupted.
 10. The catheter of claim 1, wherein the tube frame andPTFE liner form an assembly having an average stiffness between 0.03N/mm and 0.10 N/mm along a substantial length thereof.
 11. The catheterof claim 1, wherein the tube frame and PTFE liner form an assembly thatis pushable through a curve having a radius of approximately 2.5 mmwithout kinking.
 12. The catheter of claim 1, wherein the tube frame isconstructed from a nitinol tube and has a wall thickness betweenapproximately 0.0254 mm and approximately 0.254 mm.
 13. The catheter ofclaim 1, further comprising: a tongue element extending from a proximalsegment of the tube frame; and a push member having a proximal regionand a distal region, wherein the tongue element is directly coupled tothe distal region of the push member.
 14. The catheter of claim 13,wherein the lumen of the tube frame has a diameter sufficient to receivean interventional cardiology device therethrough.
 15. A guide catheterextension, comprising: a push member having a proximal region and adistal region; a distal assembly comprising: a nitinol tube frame havinga plurality of cuts therein, the tube frame defining a longitudinalaxis, a lumen therethrough having a diameter sufficient to receive aninterventional cardiology device therethrough, and a proximal opening ofthe lumen; and a PTFE liner disposed within the lumen, wherein the lineris intermittently bonded to the tube frame along a length thereof bymelted polyether block amide powder; and a tongue element extending froma proximal segment of the distal assembly, wherein the tongue element isdirectly coupled to the distal region of the push member.
 16. The guidecatheter extension of claim 15, wherein the distal assembly has anaverage stiffness between 0.03 N/mm and 0.10 N/mm along a substantiallength thereof.
 17. The guide catheter extension of claim 15, whereinthe distal assembly is pushable through a curve having a radius ofapproximately 2.5 mm without kinking.
 18. The guide catheter extensionof claim 15, wherein the tube frame is constructed from a nitinol tubeand has a wall thickness between approximately 0.0254 mm andapproximately 0.254 mm.
 19. The guide catheter extension of claim 15,further comprising a polymer flare circumscribing the proximal openingof the lumen, wherein the flare has a greater diameter than an outerdiameter of the tube frame, and wherein the tongue element extendsthrough an opening defined by the flare.